/*
 * pthread emulation for re-entrant libcs
 *
 * We can't use pthreads directly, so why not let libcs
 * that wants pthreads use Wine's own threading instead...
 *
 * Copyright 1999 Ove Kåven
 */

#include "config.h"

#include <errno.h>
#include <stdlib.h>
#include <unistd.h>

#include "winbase.h"
#include "heap.h"
#include "thread.h"

/* Currently this probably works only for glibc2,
 * which checks for the presence of double-underscore-prepended
 * pthread primitives, and use them if available.
 * If they are not available, the libc defaults to
 * non-threadsafe operation (not good). */

#if defined(__GLIBC__)
#include <pthread.h>

#ifdef NEED_UNDERSCORE_PREFIX
# define PREFIX "_"
#else
# define PREFIX
#endif

/* adapt as necessary (a construct like this is used in glibc sources) */
#define strong_alias(orig, alias) \
 asm(".globl " PREFIX #alias "\n\t.set " PREFIX #alias "," PREFIX #orig)

/* NOTE: This is a truly extremely incredibly ugly hack!
 * But it does seem to work... */

/* assume that pthread_mutex_t has room for at least one pointer,
 * and hope that the users of pthread_mutex_t considers it opaque
 * (never checks what's in it) */
typedef struct {
  CRITICAL_SECTION *critsect;
} *wine_mutex;

typedef struct _wine_cleanup {
  void (*routine)(void *);
  void *arg;
} *wine_cleanup;

typedef const void *key_data;

#define FIRST_KEY 0
#define MAX_KEYS 16 /* libc6 doesn't use that many, but... */

static CRITICAL_SECTION init_sect = CRITICAL_SECTION_INIT;

#define P_OUTPUT(stuff) write(2,stuff,strlen(stuff))

void __pthread_initialize(void)
{
}

int __pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
{
  static pthread_once_t the_once = PTHREAD_ONCE_INIT;

  EnterCriticalSection(&init_sect);
  if (!memcmp(once_control,&the_once,sizeof(the_once))) {
    (*init_routine)();
    (*(int *)once_control)++;
  }
  LeaveCriticalSection(&init_sect);
  return 0;
}
strong_alias(__pthread_once, pthread_once);

int __pthread_mutex_init(pthread_mutex_t *mutex,
                        const pthread_mutexattr_t *mutexattr)
{
  /* glibc has a tendency to initialize mutexes very often, even
     in situations where they are not really used later on.

     As for us, initializing a mutex is very expensive, we postpone
     the real initialization until the time the mutex is first used. */

  ((wine_mutex)mutex)->critsect = NULL;
  return 0;
}
strong_alias(__pthread_mutex_init, pthread_mutex_init);

static void mutex_real_init( pthread_mutex_t *mutex )
{
  EnterCriticalSection(&init_sect);

  if (!((wine_mutex)mutex)->critsect) {
    ((wine_mutex)mutex)->critsect = HeapAlloc(SystemHeap, 0, sizeof(CRITICAL_SECTION));
    InitializeCriticalSection(((wine_mutex)mutex)->critsect);
  }

  LeaveCriticalSection(&init_sect);
}

int __pthread_mutex_lock(pthread_mutex_t *mutex)
{
  if (!SystemHeap) return 0;
  if (!((wine_mutex)mutex)->critsect) 
    mutex_real_init( mutex );

  EnterCriticalSection(((wine_mutex)mutex)->critsect);
  return 0;
}
strong_alias(__pthread_mutex_lock, pthread_mutex_lock);

int __pthread_mutex_trylock(pthread_mutex_t *mutex)
{
  if (!SystemHeap) return 0;
  if (!((wine_mutex)mutex)->critsect) 
    mutex_real_init( mutex );

  if (!TryEnterCriticalSection(((wine_mutex)mutex)->critsect)) {
    errno = EBUSY;
    return -1;
  }
  return 0;
}
strong_alias(__pthread_mutex_trylock, pthread_mutex_trylock);

int __pthread_mutex_unlock(pthread_mutex_t *mutex)
{
  if (!((wine_mutex)mutex)->critsect) return 0;
  LeaveCriticalSection(((wine_mutex)mutex)->critsect);
  return 0;
}
strong_alias(__pthread_mutex_unlock, pthread_mutex_unlock);

int __pthread_mutex_destroy(pthread_mutex_t *mutex)
{
  if (!((wine_mutex)mutex)->critsect) return 0;
  if (((wine_mutex)mutex)->critsect->RecursionCount) {
#if 0 /* there seems to be a bug in libc6 that makes this a bad idea */
    return EBUSY;
#else
    while (((wine_mutex)mutex)->critsect->RecursionCount)
      LeaveCriticalSection(((wine_mutex)mutex)->critsect);
#endif
  }
  DeleteCriticalSection(((wine_mutex)mutex)->critsect);
  HeapFree(SystemHeap, 0, ((wine_mutex)mutex)->critsect);
  return 0;
}
strong_alias(__pthread_mutex_destroy, pthread_mutex_destroy);

int __pthread_atfork(void (*prepare)(void),
		     void (*parent)(void),
		     void (*child)(void))
{
  /* are we going to fork? nah */
  return 0;
}
strong_alias(__pthread_atfork, pthread_atfork);

int __pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
  return 0;
}
strong_alias(__pthread_mutexattr_init, pthread_mutexattr_init);

int __pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
{
  return 0;
}
strong_alias(__pthread_mutexattr_destroy, pthread_mutexattr_destroy);

int __pthread_mutexattr_setkind_np(pthread_mutexattr_t *attr, int kind)
{
  return 0;
}
strong_alias(__pthread_mutexattr_setkind_np, pthread_mutexattr_setkind_np);

int __pthread_mutexattr_getkind_np(pthread_mutexattr_t *attr, int *kind)
{
  *kind = PTHREAD_MUTEX_RECURSIVE_NP;
  return 0;
}
strong_alias(__pthread_mutexattr_getkind_np, pthread_mutexattr_getkind_np);

int __pthread_mutexattr_settype(pthread_mutexattr_t *attr, int kind)
{
  return 0;
}
strong_alias(__pthread_mutexattr_settype, pthread_mutexattr_settype);

int __pthread_mutexattr_gettype(pthread_mutexattr_t *attr, int *kind)
{
  *kind = PTHREAD_MUTEX_RECURSIVE_NP;
  return 0;
}
strong_alias(__pthread_mutexattr_gettype, pthread_mutexattr_gettype);

int __pthread_key_create(pthread_key_t *key, void (*destr_function)(void *))
{
  static pthread_key_t keycnt = FIRST_KEY;
  EnterCriticalSection(&init_sect);
  *key = keycnt++;
  LeaveCriticalSection(&init_sect);
  return 0;
}
strong_alias(__pthread_key_create, pthread_key_create);

int __pthread_key_delete(pthread_key_t key)
{
  return 0;
}
strong_alias(__pthread_key_delete, pthread_key_delete);

int __pthread_setspecific(pthread_key_t key, const void *pointer)
{
  TEB *teb = NtCurrentTeb();
  if (!teb->pthread_data) {
    teb->pthread_data = calloc(MAX_KEYS,sizeof(key_data));
  }
  ((key_data*)(teb->pthread_data))[key] = pointer;
  return 0;
}
strong_alias(__pthread_setspecific, pthread_setspecific);

void *__pthread_getspecific(pthread_key_t key)
{
  TEB *teb = NtCurrentTeb();
  if (!teb) return NULL;
  if (!teb->pthread_data) return NULL;
  return (void *)(((key_data*)(teb->pthread_data))[key]);
}
strong_alias(__pthread_getspecific, pthread_getspecific);

void _pthread_cleanup_push(struct _pthread_cleanup_buffer *buffer, void (*routine)(void *), void *arg)
{
  ((wine_cleanup)buffer)->routine = routine;
  ((wine_cleanup)buffer)->arg = arg;
}

void _pthread_cleanup_pop(struct _pthread_cleanup_buffer *buffer, int execute)
{
  if (execute) (*(((wine_cleanup)buffer)->routine))(((wine_cleanup)buffer)->arg);
}

void _pthread_cleanup_push_defer(struct _pthread_cleanup_buffer *buffer, void (*routine)(void *), void *arg)
{
  _pthread_cleanup_push(buffer, routine, arg);
}

void _pthread_cleanup_pop_restore(struct _pthread_cleanup_buffer *buffer, int execute)
{
  _pthread_cleanup_pop(buffer, execute);
}

pthread_t pthread_self(void)
{
  return (pthread_t)GetCurrentThreadId();
}

int pthread_equal(pthread_t thread1, pthread_t thread2)
{
  return (DWORD)thread1 == (DWORD)thread2;
}

int pthread_setcanceltype(int type, int *oldtype)
{
  if (oldtype) *oldtype = PTHREAD_CANCEL_ASYNCHRONOUS;
  return 0;
}

#endif /* __GLIBC__ */